An on-board diagnostic (OBD in short hereinafter) device is installed on a vehicle and connected to a computer of the vehicle to get executing conditions and set data of the vehicle computer to determine whether the vehicle has malfunction.
In general, a driver usually installs a display, such as a head up display (HUD in short hereinafter), through an adapter inserted into a socket of the OBD to capture and display vehicle driving information. For instance, R.O.C. patent No. M338779 discloses an HUD device connected to a socket of an OBD-II to get information and supply power, and also perform decoding and conversion. The HUD device includes a 16 pin to 4 pin adapter inserted into an OBD-II socket, a metal conductive wire set connected to the adapter, an electronic integrated host having a communication conversion unit processor and a control circuit board with HUD function. When a vehicle is started to form electrical connection, power supply is provided and signal is captured. When in use, the communication conversion unit processor accesses related signals and decodes various communication protocol signals to become input signals required for the display for displaying.
While the aforesaid conventional technique can transmit vehicle driving information through the adapter to the HUD device for displaying, the format of the vehicle driving information transmitted through the adapter cannot be recognized by the display. Hence the vehicle driving information must be accessed by a communication conversion unit processor (namely a controller area network transceiver) in the HUD device and converted into a format which can be recognized by the display for displaying.
Thus the adapter can only be inserted into a specific electronic device, namely the one equipped with the aforesaid communication conversion unit processor such as the HUD device. As a result, the specification of external devices connected to the adapter is limited so that the adapter cannot be widely adapted to other external devices such as mobile phones, computers, PDAs or the like.